I'm pretty sure the RAM worked fine on other computers, when I tested it. Also I'll try a brand new CMOS batter later.

The fact that no RAM was detected would seem to indicate that the MB is fine but does not indicate the RAM is fine. And use a brand new CMOS battery as one from another system may be borderline good. They are cheap and can be found at most dollar stores, electronic stores, and PC shops.

Depending on the age of your 7050 it could be a BIOS Checksum Failure or an Invalid Memory error. Try reseating the RAM. If that does not help pull all the RAM and try to boot. You should get beeps or a diagnostic light sequence indicating no RAM installed. If you do then install only 1 RAM module and try to boot. If that does not help try another RAM module, the purpose is to find out if you have a bad RAM module. If that does not help and considering the BIOS error possibility, it could be a MB problem. 

Just a thought, did you install a brand new recently purchased CMOS battery? 

I just tried re-seating the RAM, but that didn't do anything. Trying to power it without any RAM installed makes it beep a few times and the amber light blinks. I assume that means it's not a RAM issue?

Also, no I don't have any brand new CMOS batteries, I just tried one from another working desktop.

I tried a different RAM but the issue persists. I tried a different CMOS battery and nothing happened.

Hey brother, did you get a solution to this? I have the exact same problem with a Dell Optiplex 3050 SFF. Blinks 2 amber and 5 white lights just as you have described. Tried reseating the RAMs, replaced the CMOS battery but still stuck. Any help?

I had such an issue, while trying to upgrade the RAM. Only the original RAM worked.

It worked after updating the BIOS.

Optiplex 7010

@Dennow​ hi, was your computer fixed? my dell optiplex 3050 SFF has the same problem